Mozilla Delivers Faster, Sharper Firefox 18

Mozilla has released Firefox 18, which gives the company’s flagship desktop browser a new, faster JavaScript engine, support for Retina screen Macs and preliminary support for WebRTC.

Existing users will be automatically updated. If you’ve opted out of auto-update or just want to try out the latest version of Firefox, head on over to the Mozilla downloads page.

This release is largely focused on speeding up Firefox and marks the public debut of a new faster JavaScript JIT compiler dubbed “IonMonkey.” IonMonkey replaces the older TraceMonkey and joins JagerMonkey as one of the two JIT compilers that make up Firefox’s SpiderMonkey JavaScript engine.

Too many monkeys? Here’s the bottom line: Firefox 18 has a faster JIT compiler, which means JavaScript-heavy web apps, games and pages like Gmail should be faster. If you’d like more of the gory details on Firefox’s various JavaScript monkeys, see our review of the beta channel release.

Web developers get a few new features to test in this release, including support for more of WebRTC and the latest CSS 3 Flexible Box Model syntax. The latter is still disabled by default. To enable it open up about:config and search for “flexbox.”

Another welcome, but disabled-by-default feature is a setting to stop insecure content from loading on secure websites. Turning it on may break a lot of sites (mixing HTTP and HTTPS content on the same page is, sadly, quite common), but it will make your browsing more secure. Head to about:config and search for “mixed,” which will bring up the relevant options.

For more details on everything that’s new in Firefox 18 — including a new HTML scaling algorithm that promises to make images sharper — be sure to read through Mozilla’s release notes.